U.S. patent application number 10/563992 was filed with the patent office on 2010-07-01 for antiglare system for a vehicle.
Invention is credited to Hans-Dieter Bothe, Thomas Engelberg, Heiko Freienstein, Reiner Marchthaler, Hoang Trinh, Matthias Wellhoefer.
Application Number | 20100165099 10/563992 |
Document ID | / |
Family ID | 34089068 |
Filed Date | 2010-07-01 |
United States Patent
Application |
20100165099 |
Kind Code |
A1 |
Marchthaler; Reiner ; et
al. |
July 1, 2010 |
Antiglare system for a vehicle
Abstract
An antiglare system in a vehicle includes a device for
controlling antiglare means. The device includes at least one image
acquisition means. The antiglare means is controlled as a function
of a first signal of the image acquisition means. The light
intensity in the passenger compartment of the vehicle is taken into
account in controlling the antiglare means.
Inventors: |
Marchthaler; Reiner;
(Gingen, DE) ; Bothe; Hans-Dieter; (Seelze,
DE) ; Trinh; Hoang; (Ditzingen, DE) ;
Freienstein; Heiko; (Weil der Stadt, DE) ; Engelberg;
Thomas; (Hildesheim, DE) ; Wellhoefer; Matthias;
(Stuttgart, DE) |
Correspondence
Address: |
KENYON & KENYON LLP
ONE BROADWAY
NEW YORK
NY
10004
US
|
Family ID: |
34089068 |
Appl. No.: |
10/563992 |
Filed: |
July 22, 2004 |
PCT Filed: |
July 22, 2004 |
PCT NO: |
PCT/DE04/01628 |
371 Date: |
May 31, 2006 |
Current U.S.
Class: |
348/135 ;
348/E7.091 |
Current CPC
Class: |
B60J 3/0204 20130101;
B60J 3/04 20130101 |
Class at
Publication: |
348/135 ;
348/E07.091 |
International
Class: |
H04N 7/18 20060101
H04N007/18 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 4, 2003 |
DE |
103 35 600.2 |
Feb 17, 2004 |
DE |
10 2004 007521.2 |
Claims
1-19. (canceled)
20. An antiglare system for a vehicle, comprising: an antiglare
mechanism; and a control device for controlling the antiglare
mechanism, the control device including at least one image
acquisition mechanism, wherein the control device controls the
antiglare mechanism as a function of a signal derived from the
image acquisition mechanism, and wherein the signal derived from
the image acquisition mechanism includes data regarding at least
one of a head position and a face-covering of at least one vehicle
occupant.
21. The antiglare system as recited in claim 20, wherein the data
regarding the head position includes an eye position of the at
least one vehicle occupant.
22. The antiglare system as recited in claim 20, wherein the data
regarding the head position includes an occupant class of the at
least one vehicle occupant.
23. The antiglare system as recited in claim 22, wherein the at
least one image acquisition mechanism is a stereo video sensor for
monitoring a passenger compartment of the vehicle.
24. The antiglare system as recited in claim 22, wherein the
control device is operatively coupled to a restraint system for the
at least one vehicle occupant.
25. The antiglare system as recited in claim 20, wherein the
face-covering is a pair of sunglasses.
26. The antiglare system as recited in claim 20, wherein the
control device identifies at least one shadow edge.
27. The antiglare system as recited in claim 20, wherein the
control device identifies a light intensity.
28. The antiglare system as recited in claim 26, wherein the
control device generates the signal derived from the image
acquisition mechanism as a function of activation of the antiglare
mechanism.
29. The antiglare system as recited in claim 27, wherein the
control device generates the signal derived from the image
acquisition mechanism as a function of activation of the antiglare
mechanism.
30. The antiglare system as recited in claim 29, wherein the
control device regulates the brightness of the image acquisition
mechanism as a function of the signal derived from the image
acquisition mechanism.
31. The antiglare system as recited in claim 27, wherein the
control device controls activation of the antiglare mechanism, and
wherein the control device takes into account a model of the
passenger compartment of the vehicle when activating the antiglare
mechanism.
32. The antiglare system as recited in claim 27, wherein the
control device controls activation of the antiglare mechanism, and
wherein the control device takes into account a second signal from
an additional sensor system when activating the antiglare
mechanism.
33. An antiglare system for a vehicle, comprising: an antiglare
mechanism; and a control device for controlling the antiglare
mechanism, the control device including at least one image
acquisition mechanism, wherein the control device controls the
antiglare mechanism as a function of a first signal of the image
acquisition mechanism, and wherein the image acquisition mechanism
is sensitive only to a partial range of the spectrum, and wherein
the antiglare mechanism reduces penetration of light into the
vehicle for the partial range of the spectrum to which the image
acquisition mechanism is sensitive.
34. The antiglare system as recited in claim 33, wherein the
antiglare mechanism is bonded to a window of the vehicle.
35. The antiglare system as recited in claim 33, wherein the
control device controls the antiglare mechanism to varying degrees
of glare reduction.
36. The antiglare system as recited in claim 33, wherein the
antiglare mechanism has a predefined attenuation value for a
predefined spectral range.
37. The antiglare system as recited in claim 33, wherein the image
acquisition mechanism is sensitive to the infrared range of the
spectrum.
38. The antiglare system as recited in claim 33, wherein the image
acquisition mechanism is sensitive to at least a narrow portion of
the visible range of the spectrum.
39. The antiglare system as recited in claim 33, further
comprising: an illumination mechanism for illuminating the
passenger compartment of the vehicle in the partial range of the
spectrum to which the image acquisition mechanism is sensitive.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an antiglare system for a
vehicle.
BACKGROUND INFORMATION
[0002] Published German patent document DE 100 12 799 describes a
device for activating an antiglare means as a function of an
illumination of a vehicle occupant's face.
SUMMARY
[0003] The device according to the present invention for activating
an antiglare means in a vehicle has the advantage over the prior
art that it takes into account the head position, and thus the
posture, of the vehicle occupant when activating the antiglare
means. In addition, a face cover may advantageously be taken into
account. In most cases, this face cover is a pair of sunglasses,
which cause the antiglare means not to be activated, since the
vehicle occupant is sufficiently protected from glare by the
sunglasses. Antiglare means may be understood here as a mechanical
antiglare means such as blinds or shutters, which is selectively
unrolled to a greater or lesser degree when operated, covering the
windows of the vehicle to a greater or lesser degree and thus at
least reducing a glare. However, an antiglare means as defined in
the present invention also includes means integrated into the
window panes themselves. For example, it includes an
electrochromatic glass whose transmission properties may be altered
by applying a voltage. The glass may thus be darkened, thus at
least reducing the glare for the vehicle occupants. An antiglare
means is understood in general as a device for darkening different
windows in a vehicle. The different windows may also be darkened
independently. For example, if it has been determined that glare is
due to the rear view mirror, the corresponding windows are
darkened, but not those through which the light reflected by the
rear view mirror does not enter the vehicle. All in all, the
vehicle occupants are thus better protected from glare, which
improves driving safety and driving comfort.
[0004] Automatic setting and adjustment of the antiglare system
alleviates the burden on the vehicle occupants, in particular on
the vehicle driver. The use of electrochromatic glass or other
transparent materials having adaptive transmission properties makes
direct and simple integration of the antiglare means into all
vehicle windows possible. The use of an antiglare means also
improves the readability of a head-up display if the vehicle is so
equipped. The device according to the present invention makes
brightness measurement using photocells unnecessary. Sun screens
may also be avoided. Avoiding sun screens provides more options for
integrating image acquisition sensors, i.e., in particular the
option of optical detection of the vehicle's passenger compartment.
The image quality of image acquisition and deep image acquisition
sensors in the passenger compartment is improved by suppressing or
reducing the influence of external light. The use of an antiglare
system in the vehicle windows, in particular the lateral windows,
makes a dimmable design of the outside mirror unnecessary. The same
holds true for the design of the inside mirrors.
[0005] It is advantageous in particular that the eye position of
the vehicle occupants is taken into account when activating the
antiglare means. Setting adaptive antiglare protection with the
highest efficiency is made possible when the instantaneous eye
position is known. Information about the class of occupants may
also be used for activating the antiglare means. It is furthermore
advantageous that the image acquisition means for monitoring the
vehicle occupants may be a stereo video sensor for passenger
compartment monitoring. In particular, the device may be linked to
a restraint system which uses such a stereo video sensor to
recognize and classify the vehicle occupants. An additional use is
thus created for a passenger compartment monitoring system.
[0006] It is furthermore advantageous that a shadow edge is
identified when the signal is generated for determining the glare.
This provides more accurate information about the degree of glare.
In addition, it allows the antiglare means to be better activated.
The light intensity may also be used for this purpose. In addition,
the first signal may advantageously also be generated as a function
of the activation of the antiglare means. This makes a regulation
mechanism possible for monitoring the effects of activation of the
antiglare means, which results in fine regulation of the antiglare
means. Brightness regulation of the image acquisition means may be
provided as a function of the device's signal. The quality of the
image detected by the image acquisition means may thus be improved.
A model of the passenger compartment may also be taken into account
when activating the antiglare means to optimize the lighting
conditions when adjusting the antiglare means. A signal of an
additional sensor system may also be taken into account when
activating the antiglare means. This includes e.g., sensors for
measuring the steering angle or the rate of change of the steering
angle, as well as video sensors for detecting the surroundings of
the vehicle. Other environmental sensor types are also possible
here. For example, the dynamics of the regulation unit may be
adjusted via the vehicle velocity and via the external sensor
system, which is highly advantageous in particular in city driving
or in tunnels. Steering angle detection allows optimum adjustment
of the antiglare means when cornering.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 shows a block diagram of a first example embodiment
of the device according to the present invention.
[0008] FIG. 2 shows a block diagram illustrating some of the
component functions of an example embodiment of the device
according to the present invention.
[0009] FIG. 3 shows a block diagram of a third example embodiment
of the device according to the present invention.
[0010] FIG. 4 shows a block diagram of a fourth example embodiment
of the device according to the present invention.
[0011] FIG. 5 shows a block diagram of a fifth example embodiment
of the device according to the present invention.
[0012] FIG. 6 shows an example of the actuator system of the
antiglare means.
[0013] FIG. 7 shows a schematic diagram of the electrochromatic
glass.
[0014] FIG. 8 shows an example of a vehicle window having a
selectively absorbent layer.
[0015] FIG. 9 shows an example of a vehicle window having a
controllable, selectively absorbent layer.
DETAILED DESCRIPTION
[0016] The present invention provides a device for activating an
antiglare means, which results in adaptive protection of the
vehicle occupants against direct or indirect glare as a function of
their belonging to a certain class of individuals, e.g., adult
occupants or child in a child seat, their posture, their
three-dimensional head position, their three-dimensional eye
position with respect to the passenger compartment geometry, their
eye position in the image and their viewing direction, and as a
function of the intensity of the glare and the areas exposed to
glare. When the antiglare system is automatically set and adjusted,
functions provided by optical image acquisition sensors and active
image acquisition sensors, for example, detection, locating and
tracking of occupant heads and eyes for seat occupancy
classification and the determination of the occupants' postures may
be used, this information also being provided for adaptive
activation of motor vehicle restraint systems. By suitably setting
the antiglare system, the lighting conditions in the passenger
compartment may in turn be optimally adjusted for the above-named
optical image acquisition and deep image acquisition sensors.
[0017] When glass or transparent materials having adjustable
transmission properties which may be integrated into the vehicle
windows are used, such as electrochromatic glass, the present
invention provides good readability of head-up displays in the
vehicle, for example, on the front windshield, regardless of the
incidence of light and for any postures, head positions and viewing
directions of the vehicle occupants.
[0018] The present invention allows conventional sun screens to be
replaced by novel antiglare systems which may be integrated into
the vehicle windows and whose light-transmission properties are
adjustable, or which may be designed as movable blinds or
shutters.
[0019] The present invention also relates in general to glare
protection of all vehicle windows, i.e., the front windshield as
well as the side windows, the rear window, and, if present, the
sunroof window.
[0020] The antiglare means such as glass having adaptive
transmission properties may be adjusted gradually or stepwise from
totally transparent to semi-transparent, while the visibility of
the road must always be ensured. In addition, the antiglare means
may be composed of a plurality of individually activatable
protection elements.
[0021] In addition to automatic setting and adjustment, the
antiglare means may be switched over to manual operation using
suitable operating elements, for example, via a switch.
[0022] FIG. 1 shows a first block diagram of the device according
to the present invention. A vehicle occupant 10 in a vehicle seat
is detected by an image acquisition sensor 11, the eye position and
the three-dimensional head position, as well as the posture of the
vehicle occupant being detected in particular. To determine the
antiglare protection, the light intensity on the face of vehicle
occupant 10 is detected. Glare may result not only from direct
light from the front or a side but also from indirect light via a
rear-view mirror 12 and external mirror 13. The vehicle has an
adaptive antiglare means 15 in the vehicle window for glare
protection. Adaptive antiglare means 15 is activated by regulator
16, which activates the antiglare means as a function of a signal
from an image processing means 14, which in turn processes the
signals of image acquisition sensor 11. Regulator 16 receives
sensor status information regarding the occupant class, posture,
head position, eye position, and viewing direction of the vehicle
occupant, as well as glare zones and glare intensities from image
processing means 14. In addition, regulator 16 uses data from a
database 17, which includes parameter sets and characteristic
curves for activating the antiglare system. Image processing means
14, regulator 16, and database 17 may all be integrated in a
control unit of the vehicle.
[0023] Image acquisition sensor 11 is a video sensor here, which
detects the vehicle's passenger compartment at a wide angle. This
allows not only the front seats, but also optionally the back seats
to be detectable. The side windows that may be relevant for the
glare, as well as the inside and outside rear-view mirrors, may
also be included in the detection range of sensor 11. The images
delivered by sensor 11 are supplied to image processing block 14 as
input quantities. The algorithms required for activating the
antiglare system according to the present invention are implemented
in image processing block 14. This essentially includes the
following algorithms: Image pre-processing, classification of the
occupants in their postures, detection, locating and tracking of
heads, eye location and sensor self-monitoring. In addition,
detection, locating of the glare zones, and determination of the
intensity in these glare zones are provided. For example,
excessively or insufficiently illuminated image zones may be
detected and located using this method. This includes the location
of shadow edges, the measurement of absolute intensity, and the
combination of these two parameters, as well as the effect of
slight changes in the sun screen or the antiglare means and
appropriate follow-up of the confirmation of or response to the
movement of the shadow edge.
[0024] The output quantities of image processing block 14 may
include the occupant class and the occupant posture, the head
position, the eye position and the viewing direction of the
occupants, but, in the simplest case, of the driver only, the glare
zones, the glare intensity, and the sensor status. The
above-mentioned output quantities of image processing block 14 as
well as the parameter sets and characteristic curves from a
database 17 form the input quantities of regulator 16, which is
responsible for setting and adjusting actuator system 15 of the
antiglare system. This essentially includes the adaptive antiglare
means on the vehicle windows, for example, windows made of
electrochromatic glass, blinds or shutters, dimmable mirrors, for
example, mirrors made of electrochromatic glass. If the antiglare
means includes electrochromatic glass, its transmission properties
are modified by applying a voltage, i.e., the glass may thus be
darkened, for example. FIG. 1 shows the antiglare means on the
front windshield and on the side window as an example. In
principle, however, all other vehicle windows may also be thus
equipped.
[0025] In addition to antiglare regulation, brightness regulation
of the image acquisition sensor may also be performed to improve
its image quality.
[0026] FIG. 2 shows a block diagram illustrating some of the
component functions of an example embodiment of the device
according to the present invention. Stereo images 25 of image
acquisition sensor 11 are supplied to pre-processing means 20. A
plurality of tasks are performed simultaneously based on the signal
of pre-processing means 20. These include sensor self-monitoring
21, head detection or head tracking, eye location 22,
classification of occupants or postures, and detection and locating
of the glare zones of the image in block 24. The result is a vector
containing different data. This vector 26 includes the sensor
status from sensor self-monitoring means 21, occupant
classification, posture, head position, eye position, and viewing
direction of the vehicle occupant, as well as glare zones and glare
intensities.
[0027] FIG. 3 shows a block diagram of a third example embodiment
of the device according to the present invention. A vehicle
occupant 30 in a vehicle seat is monitored by an image acquisition
sensor 32. Vehicle occupant 30 sees an external rear-view mirror 31
and an internal rear-view mirror 33. An adaptive antiglare means is
provided on vehicle window 35 to protect vehicle occupant 30 from
glare. The signals of image acquisition sensor 32 are processed by
an image processing means 34 to determine the sensor status, the
occupant class, position, head position, eye position, and viewing
direction of the vehicle occupant, as well as glare zones and glare
intensities. This data is supplied to a regulator 36, which also
takes into account a CAD model of passenger compartment 37 and data
from a database 38. This data includes parameter sets and
characteristic curves for activating the antiglare system.
Regulator 36 then activates antiglare means 35 as a function of
this data, the antiglare means including those of the external and
internal rear-view mirrors. CAD model 47 results in better
adaptation of the antiglare system regulation to the passenger
compartment geometry.
[0028] FIG. 4 shows a block diagram of another example embodiment
of the device according to the present invention. A vehicle
occupant 43 in a vehicle seat is monitored by an image acquisition
sensor 40. Vehicle occupant 43 again sees an internal rear-view
mirror 41 and an external rear-view mirror 42. An adaptive
antiglare means is provided on vehicle window 45 to protect vehicle
occupants 43 from glare. The signals of image acquisition sensor 40
are processed by an image processing means 44. The result vector is
composed of the sensor status, occupant class, posture, head
position, eye position, and viewing direction of the vehicle
occupant, as well as glare zones and glare intensities. This data
is supplied to a regulator 46, which activates antiglare means 45.
However, regulator 46 also takes into account a CAD model of
passenger compartment 47 and data from a database 48, which
includes parameter sets and characteristic curves for activating
the antiglare system. In this case the antiglare means is designed
such that the vehicle occupants are protected from indirect glare
via the mirrors by appropriate darkening of the relevant areas of
the vehicle windows. In this case, simple, non-dimmable mirrors may
be used.
[0029] FIG. 5 shows a block diagram of another example embodiment
of the device according to the present invention. A vehicle
occupant 59 is detected by an image acquisition sensor 50. Vehicle
occupant 59 sees an external rear-view mirror 58 and an internal
rear-view mirror 51. An adaptive antiglare means 53 is provided to
protect vehicle occupant 59 from glare. The signals of image
acquisition sensor 50 are processed by image processing means 52 to
determine the above-described data. This data is supplied to a
regulator 54, which activates antiglare means 53 as a function
thereof. However, in addition, the regulator also takes into
account a model of the passenger compartment and data of a database
56. Regulator 54 also takes into account data from other sensors
such as a surroundings sensor system for the vehicle
surroundings.
[0030] In addition to this data, sensors for measuring the vehicle
velocity and the steering angle and the above-mentioned
surroundings sensors may be used as data sources for regulator 54.
For example, the dynamics of the regulator may be adjusted via the
vehicle velocity and via the surroundings sensor system, for
example, when driving in the city or in a tunnel. Steering angle
detection allows optimum adjustment of the antiglare system when
cornering.
[0031] FIG. 6 shows an example of the actuator system of the
antiglare means as shutter or blinds 60. The actuator system is
situated appropriately in front of a vehicle window 61. FIG. 7
shows a schematic diagram of the electrochromatic glass. In this
case, the structure of antiglare means 70 includes individually
controllable individual elements 71, which are able to apply an
electric voltage to the electrochromatic glass to darken individual
areas differently.
[0032] In an example embodiment of the present invention, a video
camera is provided as an imaging device, which is equipped with
antiglare means in such a way that it is sensitive only in a
predefined spectral range. In one example embodiment, this
sensitive spectral range may include at least one narrow range of
the visible spectrum. In another example embodiment, this spectral
range may be situated in the infrared range of the spectrum. In
order to ensure proper passenger compartment illumination which
remains as constant as possible, a light source adapted to the
sensitivity range of the image acquisition means may be provided.
To further improve the image quality of the image acquisition
means, external light effects that interfere with the antiglare
system of the vehicle are largely reduced or fully suppressed. For
this purpose, the antiglare means situated in the vehicle windows
is controlled in such a way that interfering spectral components of
the light penetrating the passenger compartment from the outside
are filtered. For example, if the image acquisition means is
sensitive in the infrared range and, if necessary, illumination
means operating in this spectral range are switched to the active
mode, the antiglare means situated in the vehicle windows is
controlled in such a way that it largely prevents the infrared
radiation from penetrating the passenger compartment. However, if
an image acquisition means which is sensitive only in a narrow
range or several narrow ranges of the visible spectrum is provided,
the antiglare means is controlled in such a way that just this
narrow range or these narrow ranges of the spectrum are suppressed
from the radiation penetrating the passenger compartment from the
outside.
[0033] In general, it must be ensured that the vision of the
vehicle occupants, in particular of the driver, is not impaired by
the above-described filtering of the light, so that the driver is
able to accurately follow the traffic. Fewer problems are to be
expected when partial ranges of the infrared spectrum are
suppressed, because these are not perceived by the human eye
anyway. When partial ranges of the visible spectrum are suppressed,
the antiglare means may be controlled in such a way that it
practically functions as a notch filter, which makes the driver
register a slight coloring, which, however, is not particularly
disturbing. By effectively suppressing interfering spectral
components as described above, the passenger compartment is
effectively illuminated, from the point of view of the image
acquisition means, only by the illumination system tuned to the
image acquisition means. This illumination system is advantageously
tuned to the sensitivity of the image sensor of the image
acquisition means. This results in contrast relationships which are
largely independent of the external lighting situations, but are
optimized for the image acquisition means, yielding substantially
improved passenger compartment detection.
[0034] This antiglare system is advantageously applicable with
different types of image acquisition means, such as mono and stereo
camera systems, monochromatic and color cameras, thermal imaging
devices, or, with similarly good results, also with image
acquisition means using propagation time measurements such as LIDAR
and radar systems. The above-described method makes it possible to
achieve better and more reliable functionality of the image
acquisition means. Furthermore, these measures allow technically
complex and therefore expensive imaging systems having a higher
input dynamics (for example, >96 dB) to be avoided. The
attenuation of the interfering spectral ranges has such a magnitude
that it allows the dynamics of the image acquisition means to be
reduced to approximately 8 bits (<approx. 48 dB). In this case,
inexpensive components already available from mass production may
be used for the image acquisition means. This allows the system
costs to be substantially reduced, which, in turn, results in these
useful safety-enhancing systems finding widespread use. This
embodiment of the present invention is further elucidated below
with reference to FIGS. 8 and 9. FIGS. 8 and 9 show as an example a
vehicle window 81, which has a layer 82 functioning as an antiglare
means. In the exemplary embodiment of FIG. 9, this layer 82 is
applied to the inside of vehicle window 81 facing the passenger
compartment. In another exemplary embodiment of the present
invention, however, this layer 81 may also be applied to the
outside of vehicle window 81 or integrated into window 81. The
latter variant is implementable in a particularly easy manner in
connection with a safety glass having a plurality of layers. Layer
82 is connected to a control unit 90. Control unit 90 is in turn
connected to at least one sensor 91. Layer 82 is advantageously
controllable in such a way that its transmission properties may be
affected by appropriate control signals of control unit 90. In
particular, the layer is controllable in such a way that it
selectively absorbs the light from the outside, which is
represented here by arrow 80, so that only a portion of the
spectrum, represented here by arrow 83, is able to penetrate the
passenger compartment of the vehicle. In this way, effective glare
protection may be implemented for the vehicle occupants, in
particular for the image acquisition means monitoring the passenger
compartment of the vehicle. Therefore, layer 82 advantageously
suppresses those components of the spectrum in particular which are
located in the sensitivity range of the image acquisition means.
Therefore, if the image acquisition means in a system is sensitive
in particular in the infrared range of the spectrum, layer 82
filters out this component of the spectrum in particular from the
radiation penetrating from the outside. For this purpose, the
control unit analyzes signals of at least one sensor 91, which
detects the radiation penetrating the passenger compartment of the
vehicle (arrow 83).
[0035] In a simpler example embodiment of the present invention,
the filtering properties of the vehicle windows are not dynamically
controllable, but are constant. This effect may be achieved in a
simple manner as early as during the manufacturing process of the
window panes provided for the vehicle windows by optically coating
them or by applying appropriate films having filtering properties
to the windows. This simpler example embodiment of the present
invention is illustrated in FIG. 8. A vehicle window is again
labeled with reference number 81. This vehicle window 81 has a
layer 82 having a selective filtering effect. Layer 82 filters the
radiation from the outside (arrow 80) in such a way that only a
non-interfering component of the spectrum (arrow 83) penetrates the
passenger compartment of the vehicle. This embodiment is
implementable in a more cost-effective manner, but has the
disadvantage compared to the exemplary embodiment illustrated in
FIG. 9 that the filtering properties of layer 82 are not
dynamically controllable.
* * * * *